A comparative study of crystal structures and inclusion properties of fluorinated triazines

Three perfluorinated host compounds of the triazine type, namely 2,4,6-tris(pentafluorophenoxy)-1,3,5-triazine (1), 2,4,6-tris(pentafluorothiophenoxy)-1,3,5-triazine (2) and 2,4,6-tris(pentafluorophenamin)-1,3,5-triazine (3), were synthesized differing only in the linking heteroatom (O, S and NH) between the triazine core and the pentafluorophenyl groups. The crystal structures involving compounds 1, 2 and their inclusion compounds are dominated by a variety of fluorine interactions (phenyl-perfluorophenyl, C–H⋯F, F⋯F, C–F⋯πF). However, in the structure of 3, possessing additional hydrogen atoms of the linkage NH-groups, the formation of hydrogen bonds is favoured, whereas fluorine contacts are less apparent. Investigations by powder X-ray diffraction and thermogravimetric analysis revealed substantial differences in the host–guest interactions of the inclusion compounds.